 visco-elast properti len dynam visco-elast properti human monkei rabbit lens measur dynam rheomet appar elast modulu young modulu len 10 -10 dyne cm human 10 -10 dyne cm monkei rabbit loss tangent 0 3-0 4 human len 0 3-0 6 rabbit monkei lens elast moduli loss tangent lens poor depend temperatur 15 -55 frequenc oscil 0 01-25 lens linear visco-elast amplitud oscil 0 02 mm nonlinear visco- elast amplitud exceed 0 03 mm 